Continuous inductive train-control system



Nov. 1, 1927. 1,647,970

w. w. SALMON CONTINUOUS INDUCTIVE TRAIN CONTROL SYSTEM Filed Sept. 11, 1925 Train control Train Confrol T June H101 Patented Novo l, 1927.

UNITED STATE 1,647,970 OFFICE.

WILMER W. SALMON, F LARCHMON '1, NEW YORK, ASSIG-NOR TO GENERAL BAJIWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK.

CONTINUOUS INDUCTIVE TRAIN-CONTROL SYSTEM.

Application filed September 11, 1925. Serial No. 55,769.

This invention relates to automatic train control, and more particularly concerns means for checking the integrity of the carcarried receiving apparatus of a train control system of the continuous inductive type.

In applying automatic train control to railway systems, the wayside control apparatus is not ordinarily applied to the en tire trackway, certain branch lines, sidings and other sections of. trackway, over which the trafiic is not congested being left unequipped for train control operation. In

the well known continuous inductive type of train control system, the absence of control currents in the track rails acts to initiate an automatic brake application, to impose a restrictive speed limit or to retard "the progressof the train in some other suit able manner, and in order that trains may operate in unequipped or non-train control territory without the inconvenience and delay caused by automatic restriction, special means are provided to place the car-carried controlapparatus in an inactive condition when the vehicle enters such unequipped sections, and to place the car-carried apparatus in the active controlling condition when equipped territory is againentered.

One of the well known methods of pro viding such control for train operation in unequipped territory employs special track- Way means located at the entrance to nontrain control territory for transmitting distinctive influences to the vehicle and thus permitting the car-carried apparatus to be placed in the inactive condition, the re-instatement of the car-carried apparatus upon the re-entrance to train control territory being instituted by further special trackway means, or by the usual train control current at the entrance to the next equipped section.

In a system of the type described, the reinstatement of the automatic car-carried control apparatus when equipped territory is entered is dependent upon the proper operation of the car-carried inductive receiving apparatus, and in this system a failore of this apparatus While the train is traveling in unequipped territory is detected regardless of the re-mstatement of the automatic control.

With the above and other considerations mind, itis proposed in accordance with present invention to provide a system of in the operation of the car-carrie train control of the continuous inductive type in which the car-carried apparatus is placed in the inactive condition for train travel in unequipped trackway sections, and is again placed in the active condition on re-entering equipped trackway sections,

by means of distinctive influences transsystem of the type described in which ener from a car-carried source is supplied to the receiving apparatus while the vehicle is proceeding in unequipped territory, the de-energization of the receiving circuits due to the failure of any of the receiving devices causing an automatic brake application or other restriction.

Other specific 'objects, advantages and characteristic features of the invention will become apparent as the description progresses. I

In describing the invention in detail, reference will be made to the accompanying drawing in which a single figure has been shown, representing in a diagrammatic and simplified manner, the car-carried and trackway equipment of a typical traincontrol system embodying the present invention.

' The present invention is applicable to any train control system of the continuous inductiv. type, and is not limited to the System chosen for the purpose of illustrating the invention. The system shown is of the well lmown three-position continuous inductive type, employing two distinctive control currentsin the track rails which act to transthree-position control relay thereon.

Referring to the trackway apparatus shown in the drawings,'the track rails 1 have been shown divided into-blocks and sections by the insulating joints 2, the blocks H and I in equipped or train control territory, the excess energy section J, portions of the blocks K and R in unequipped or nontrain control territory, the excess energy section S and a portion of the block T in a second equipped section of trackway being. shown. In the trackway and car-carried circuits, the letters B and C have beennsed to designate the opposite terminals of a sui able source of direct current energy, preferably a storage battery. As the devices and circuits in the blocks H, I and T, in train control territory, are substantially identical, a detailed description of the equipment used in connection with the block I only wlll be given, the corresponding elements in the blocks H and T being referred to by like reference characters having' distinctive exponents.

The track phase train control current, which is also the track circuit current, is applied to the two track rails in series at the exit end of the block from the transformer 3, the primary winding of which is connected across the transmission line 4, this oncuit including the usual track reactance 5. As alternating current is applied in the present system for train control purposes in equipped territory, it is assumed that alteranting current track circuits will be used, and the alternating current track relay 6 is therefore shown connected across the track rails at the entrance end of the block, being energized by the track circuit current from the transformer 3 through a circuit including the track rails of the block, this c1r- Acuit be1ng obvious from the drawings. The

line phase or simplex train control current is supplied to the two track rails in multiple through the balance resistances 7 and 8 located at the entrance and exit ends of the block respectively. The polarity of the hue phase train control current is controlled by means of the pole changing contact fingers I 9 and 10, these contact fingers being controlled by a line relay 11 in the case of the block I, which is assumed to be the last regular block in a section of trackway which is equipped for automatic train control, the contact fingers 9 and 10 of the other blocks in train control territory being controlled by the track relay 6 in the usual manner. The line relay 11 is controlled in accordance with traffic conditions in advance as hereinafter explained. The simplex or line phase train control current is supplied to the track rails through a circuit which may be traced as follows :from the secondary winding of the transformer 12, wires 13 and 14, front contact and contact finger 9 of the line relay 11, wire 15, balance resistance 8, the track rails 1 in multiple to the entrance end of the block, balance resistance 7, wire 16, contact finger 10 and front contact of the line relay 1.1, and wire 17 to the secondarywinding of the transformer 12, the primary winding of the transformer 12, being connected across the transmission line 4. When the line relay 11 is de-energized due to unfavorable trafiic conditions in the excess energy section J or in the block K, the instantaneous polarity of the line phase or simplex train control current is reversed by the retraction of the contact fingers 9 and 10 of the line relay 11, the circuit for supplying this reversed current being obvious from the drawings.

An excess energy trackway section J is provided between the last block I in train control territory and the first block K 111 a section of track which is unequipped for train control operation. This excess energy section comprises an insulated section of track rails supplied with the usual track and line phase train control currents, these currents being of greater magnitude than those employed with the usual track blocks in equipped territory. The track phase control current in the excess energy section J is of reverse instantaneous polarity with respect to the line phase current in this section as shown by the cross connection of the wires 18 and 19 supplying this current to the track rails. In order that the control currents flowin in the track rails of the block I may re ect traflic conditions in ad- Vance, this is, trafiic conditions in the excess energ section J and in the block K, the energizing circuit for the line relay 11 is controlled through front contacts of the track relay 20 at the entrance end of the excess energy section J, and of the track relay 21 at the entrance end of the block K, this energizing circuit being obvious from the drawings.

It is obvious'that when a train is located in a given block in train control territory, or in the excess energy section J or the first block K in unequipped territory, the track phase control current will be cut off by the wheels and axles of the train in the block in which the train is located, causing the deenergizing of the track relay at the entrance end of that block, and thus reversing the instantaneous polarity of the line phase control current in the first block to the rear.

An excess energy section S is shown at the entrance to train control territory, being located between the last block R in non-train control territory and the entrance end of the first block T of train control territory. This excess energy section is supplied with track and line phase control currents of comparatively large magnitude through circuits which are obvious from the drawings, the track phase control current in the section S being of normal polarity with respect to the line phase current in this section.

Wayside signals of the color light, semaphore or other suitable type may or may not be used in connection with the present system, and the semaphore signals Z of the usual type have been illustrated in a conventional manner at the entrance ends of the various blocks, their well known operating devices and circuits being omitted in order to simplify the disclosure.

Referring now more particularly to the ill) car-carried apparatus, a railway vehicle has been represented in the block H by the wheels and axles 22, the normal direction of traffic being indicated by the arrow. Suitable inductive receiving coils 23 are mounted in inductive relation to the track rails in front of the leading axle of the vehicle, these coils being connected in such a manner that voltages induced therein b currents flowing in opposite directions in t e two track rails will be cumulative. A second pair of receiving coils 24 is carried by the vehicle in inductive relation to the track rails and at a point to the rear of at least one of the vehicle axles, preferably in the rear end of the first vehicle of the train, these coils 24 being connected in such amanner that voltages induced therein by alternating currents flowing in the two track rails in multiple will be additive. and 24 may or may not be provided with laminated iron cores. The receiving coils 23 are connected in series with the inputcircuit of a suitable amplifying device A, preferably of the audion tube type, this input circuit including the secondarywinding of the transformer25 and a resistance unit 26 as clearly shown. The receiving coils 24 are connected in series with the input circuit of av similar amplifier A through a circuit including the secondary winding of the transformer 27. Theoutput circuits of the amplifiers A and A are connected to the two field windings 28 and 29 respectively of a polyphase alternating current relay, termed the main relay MR. This relay is of a type well known in train control practice and is provided with suitable movable contact fingers 30 and 31 which act to complete various control circuits in accdrdance with the energization of the relay as hereinafter described.

The operation of the car-carried apparatus at the entrance to unequipped territory to render this apparatus inactive is accomplished by means of a manually operable circuit closer, termed thenon-control push button NB. This circuit controller may take any suitable form and has been shown in a conventional manner only, it being assumed that this device is located at some point in the vehicle cab within easy access of the engineer. The car-carried apparatus also includes a non-control relay NC, preferably of the direct current type, which acts when energized to render the car-carried control apparatus inactive as hereinafter described. Suitable cab signals, NS and TS are preferably provided in connection with the pres-' cnt system, and may take the form of small incandescent lamps or any other suitable visual or audible devices.

The automatic "control of the progress of the vehicle may be accomplishedzin any one? of different ways, but as thefin-j of a variety The receiving coils 23.

that is, that itiation of a restrictive control is usually accomplished by means of a suitable electromagnetic or electro-pneumatie device, the electro -pneumatic valve EPV has been shown for accomplishing this result. It should be understood that the deenergiza-' tion of the electro-pneumatic valve EPV acts in some suitable manner to restrict or retard the progress of the vehicle by means of an automatic brake application which persists until the vehicle speed has been reduced to a safe low value, or which may bring the vehicle to a stop before the brakes may be released and thereafter permit the vehicle to proceed only at a restricted speed. As the particular devices and circuits for accomplishing the various automatic controls mentioned are Well known to those skilled in the art and form no specific part of the present invention, this modifying control apparatus has not been shown or described.

In order to provide for the checking control which constitutes a particular feature of the present invention, a car-carried source of alternating current energy is provided in the form of the alternating current generator AC. It is assumed that this generator AC is driven by some suitable car-carried means such as a steam turbine or other prime mover Operation.

All of the devices and circuits shown in the drawings have been illustrated in their normal operating condition, that is, with the vehicle proceeding in train control territory under clear traffic conditions with certain circuits properly energized.

Considering first the operation of the train control system shown when the train is traveling in equipped sections of trackway, assume that the clear traffic conditions exist in the block H in which the train is located, no other train is located in the block H or in the first block I in advance thereof. Under these conditions, track and line phase train control currents fiow in the track rails of the block H, the track phase control current flowing through the track rails in advance of the train and through the wheels and axles thereof, and the line phase current flowing through the track rails in multiple for the entire length of the block. The track and line phase control currents induce voltages in the receiving coils 23 and 24 respectively, these voltages are impressed upon the input circuits of the amplifiers A and A respectively, and these amplifiers supply energizing currents to the field windings 28 and 29 of the main relay MR, causing this relay to be energized in the normal direction as shown.

*VVith the main relay MR energized to the normal position, a circuit is completed for energizing the. electro-pneumatic valve EPV,

which circuit may beftraced a's'j'fo1lows:--

terminal B, contact finger 30 and stationary contact of the main relay MR, wires 32 and 33 and the winding of the electro-pneumatic valve EPV to the battery terminal C. With the electro-pneumatic valve thus energized, the train under consideration may proceed in the clear territory without automatic restriction.

If a train is located in the excess energy section J or in the block K when the vehicle under consideration enters the block I, line phase control current of reverse polarity flows in the track rails of the block I, causing current of reversed instantaneous polarity to be applied to the field winding 29 of the main relay MR. Under these conditions, the main relay MR is energized in a reverse direction, thus breaking the energizing circuit for the electro-pneumatic valve EPV, traced above, and an automatic brake application results, restricting the vehicle speed to a safe low value or bringing the train to a stop according to the control system used. If a train is located in the block I, shunting the track phase control current from the track rails of this block, the field winding 28 of the main relay MB is de-energized and the relay MR assumes its de-energized position, thus breaking the energizing circuit for the electro-pneumatic valve EPV and causing an automatic restriction in some suitable manner. It should be understood that the car-carried control apparatus may include further devices for imposing distinctive brake applications or speed restrictions in danger and caution blocks, that is, blocks in which a train is located or'blocks immediately to the rear thereof.

Considering now the operation of the system shown on entering a section of trackway which is unequipped for train control operation, assume that the train under consideration passes through the block I under clear traffic conditions and enters the excess energy section J. The engineer is apprised of the fact that he is about to enter non-train control territory by his knowledge of the route or by some suitable fixed wayside indicator or marker, and depresses the non-control pushbutton NB as the train enters the section J. W'hen the non-control push button NB is depressed, the contact finger 34 of this push button disengages its front contact, thereby opening a normally closed shunt circuit around the resistance from the battery unit 26 in the input circuit of the track phase amplifier A, this normally closed shuntcircuit being traceable as follows from the resistance unit 26, wire 35, contact finger 34 and front contact of the push button NB, and wire 36 to the resistance unit 26. Since the track phase control current flowing in the rails of the excess energy section J is of a greater magnitude than that flowing in the rails of the blocks in train control territory, and is of reversed instantaneous polarity with respect to the usual track phase control current, the main relay MR is energized in a reverse direction in spite of the insertion of resistance unit 26 in the input circuit of the track phase amplifier A. \Vith the main relay MR energized in its reverse direction, and the noncont-rol button NB depressed, an energizing circuit for the non-control relay NC is completed, which circuit may be traced as follows :from the battery terminal B, contact finger 31 and stationary contact of the main relay MR, wires 37 and 38, contact finger 39 and back contact of the push button NB, wires 40 and 41 and the winding of the non-control relay NC to the battery terminal C. Once energized the non-control relay NC is maintained energized through a stick circuit which may be traced as follows :-from the battery terminal B, contact finger 31 and stationary contact of the main relay MR, wires 37 and 42, contact finger 43 and front contact of the non-control relay NG, wires 44 and 41 and the winding of the non-control relay NC to the battery terminal C.

The energization of the non-control relay NC closes a circuit for supplying car-carried energy to the input circuits of the amplifiers A and A, this circuit being traceable as follows :-from the alternating current generator AC, wire 45, contact finger 46 and front contact of the non-control relay NC, wires 47, 48 and 49 to the primary winding of the transformers 25 and 27 inparallel, wires 50, 51 and 52 to the alternating current generator AC. It should be noted that a reactance coil 53 is included in the input circuit of the transformer 25, the purpose of this reactance being to .provide a proper phase displacement between the alternating currents supplied to the input circuits of the amplifiers A and A respectively, this phase displacement being so arranged that the main relay MR will be maintained energized in a reverse direction. As the train under consideration leaves the excess energy section J, the engineer releases the push button NB and the main relay MR is maintained energized in its reverse direction by the energy supplied from the car-carried source AC, and thus the stick circuit for the non-control relay NC is maintained closed as the train proceeds in the non-train control territory.

WVith the non-control relay NC energized, a circuit is completed for maintainin the electro-pneumatic valve EPV energized, this circuit being traceable as follows :from the battery terminal B, contact finger 54 and front contact of the non-control relay NC, wires 55 and 33 and the winding of the electro-pneumatic valve EPV to the battery terminal C. With the electro-pneumatic valve remove EPV thus maintained energized, the train may proceed in the unequipped or non-train control territory without automatic restric-v tion, the engineer being apprised of the fact that the car-carried apparatus is in its proper inactive condition by means of the indication of the non-control cab signal NS which is energized when the non-control relay N O is energized through an obvious circuit including the contact finger 56 and front contact of this non-control relay.

It should be noted that the engineer cannot misuse the car-carried apparatus by depressing the non-control push button NB while the train is proceeding in train control territory and thereby avoid an automatic brake application, for the reason that the resistance unit 26 is inserted in the input circuit of the track phase amplifier A whenever the non-control push button NB is depressed. Thus if the non-control button NB is depressed under clear trafiic conditions in train control territory, the resistance unit 26 will so decrease the energy supplied to the input circuit of the amplifier A as to cause the de-energization of the field winding 28 of the main relay MR, thus de-energizing this main relay and initiating a brake application of a speed restriction as described above.

Considering now the re-entrance of the train under consideration into territory which is equipped for automatic train control, as the. train leaves the last block R in non-train control territory it enters the excess energy section S which is supplied with normal line phase control current, and track phase control current of increased magnitude, the phase relation between these two control currents in the section S being such as to cause the normal energization of the main relay MB. The magnitude of the track phase train'control current flowing in the rails of the excess energy section S is so great as to overcome the effect produced by the car-carried alternating current generator AG in the input circuits of the amplifiers A a and A, thus causing the de-energization of the main relay MB or its energization in a normal direction in which it has been shown,

. depending upon the amount of current flowing in the track rails of the section S, it bemg of course remembered that therelay MR is biased to the middle If the main relay MB is de-energized in the excess energy section S, the stick circuit to the non-control relay NC is broken, causing the de-energization of this relay and cuttin oil? the energy supply from the car-carrie source AC to the input circuits of the amplifiers A and A. The main relay MB is if so de-energized immediately re-energized in a normal direction as the train under consideration enters the first block '1 in train control territory (assuming that clear trafic tie-energized position.

condition'sexist) i1 and the electro-pneumatic valve EPV is t en re-energized to permit the train to proceed under automatic control. The engineer is informed that the carcarried apparatus is properly operated for train control territory by means of the indication of the cab signal TS which is ener gized through the contact finger 56 and back contact of the noncontrol relay NC as clearly shown.

It should of course be understood that the electro-pneumatic valve EPV and its associated control aparatus is so designed and constructed that the initiation of an automatic brake application does not follow immediately upon the de-energization of the winding of this valve EPV. The purpose of this delayed action is to permit the vehicle to proceed through the excess energy sections without a brake application, and also to prevent automatic restrictlon where short sections of trackway are traversed at switches, cross-overs, and like points, where it is diflicult or impossible to'maintain the continuity of flow of control current in the track rails.

Considering now the operation of the present system in a case in which the failure of the receiving circuits occurs while the train is proceeding in non-train control territory, assume that the train under consideration has entered the unequippcd territory with the car-carried apparatus set in its inactive condition, that is, with the non-control relay NC energized and with the main relay Mt: energized in the reverse direction from the car-carried source AC. If for any reason the car-carried receiving circuits or amphfiers are injured, burned out or in any other manner rendered inactive, the main relay MB is at once de-energized, dropping its contact fingers '30 and 31 to their vert1calde-enercont-act finger 31 and its stationary contact 7 causes the de-energization of the stick circut for the non-control relay N 0, this circuit having been traced above, and the noncontrol relay is thereby de-energized. The de-energization of the non-control rela NC results .in the retraction of its contact linger 54 and the consequent opening of the energizing circuit for the electro-pneumatic valve EPV, this circuit having been traced above, and an automatic brake application results. In this manner the engineer is informed that the receiving equipment is out of order and that this equipment must be repaired before the train may proceed without restriction in the unequipped territory. It should be understood that the-alternating current generator AC is disconnected from the input circuits of the amplifiers A and A as soon as the non-control relay NC is deenergized, so that a broken wirejn the receiving circuits will not result in the reenergization of the main relay MB if the broken ends of the wire should momentarily engage, the alternating current source AC being disconnected from the input circuits as soon as the first failure of current supplied to the relay MR occurs.

Although the present invention has been described in connection with a rather specific system of automatic train control employing certain specific devices and features, the invention is applicable to many other train control systems, and it should be clearly understood that the invention is not limited in its scope to the system shown except as indicated by the appended claims.

'What it is desired .to secure by Letters Patent is 1. In an automatic train control system of the type having sections of its trackway equipped for automatic train control and sections not so equipped, trackway means in said equipped sections for continuously transmitting influences to a moving vehicle under favorable traflic conditions, car-carried receiving means for receiving said influences while the vehicle is traveling in said equipped sections, and means for insuring the operation of said car-carried receiving means while the vehicle is proceeding in said unequipped sections comprising, a car-carried source of energy and means for supplying energy from said source to said carcarried receivin traveling in sai unequipped sections.

2. In an automatic train control system of the type having sections of its trackway equipped for automatic train control and section not so equipped, trackway means for continuously transmitting influences to a V0- hicle in said equipped sections under favorable trafiic conditions, car-carried receiving circuits for receiving said influences, control means for controlling the vehicle brakes in accordance with the reception of said in fluences, special trackway means at the entrance to said unequipped sections of trackway for transmitting distinctive influences to said car-carried receiving circuits, a manually operable car-carried device for rendcrlng said control means inactive to initiate a brake application if said device is operated while said distinctive influences are being received, and a car-carried source of energy for energizing said receiving circuits with a distinctive influence while the vehicle is travcling in said unequipped sections.

3. In an automatic train control system of the type having sections of its trackway equipped for automatic train control and sections not so equipped, means for transmitting influences continuously to a moving vehicle under favorable traflic conditions in said equipped sections, means for initiating a restr ctive control when said influences are not received, and means for preventing the means while the vehicle is initiation of said restrictive control while the vehicle is traveling in said unequipped sections including car-carried means for supplying said influences.

4. In automatic train control system of the type having sections of its trackway equipped for automatic train control and sections not so equipped, trackway means in said equipped sections for continuously transmitting influences to a vehicle under favorable traffic conditions only, ried apparatus comprising receiving circuits for receiving said influences, a control device controlled in accordance with said influences, brake applying means controlled by said control device to initiate an automatic brake application when said influences are not transmitted, trackway and car-carried means for rendering said brake applying device inactive at the entrance to said unequipped sections of trackway and car-carried means including a source of energy for supplying influences to said receiving circuits for maintaining said brake applying device inactive while the vehicle is traveling in said unequipped sections.

5. In an automatic train control system of the type having sections of its trackway equipped for automatic train control and sections not so equipped, trackway means in said equipped sections for continuously transmitting influences to a vehicle under favorable traffic conditions, vehicle-carried apparatus comprising receiving circuits for receiving said influences, a control device having a normal and a reverse position controlled in accordance with said influences, a normally energized electro-magnetic device acting to initiate an automatic brake application when de-energized and maintain energized by said control device when in its normalposition, a stick device acting when energized to maintain said normally energized electro-magnetic device energized, trackway means at the entrance to said unequipped sections of trackway for transmitting influences to move said control device to its reverse position, a pick-up circuit for vsaid stick device including contacts of said control device closed in its reverse position and a manually operable contactor. a stick circuit for said stick device including contacts of said control device closed in its reverse position. a vehicle source of energy and means controlled by said stick device for transmitting influences from said source to said receiving circuits when said stickdcvice is energized. said influences from said vehicle source acting to maintain said control device in its reverse position while the vehicle is traveling in said unequipped sections of trackway.

6. In an automatic train control system of the type having sections of its 'trackway equipped for automatic train control and vehicle-carsaid unequipped sections,

sections not so equipped, trackway means in said equipped sections for continuously transmitting certain influences to a vehicle under favorable traffic conditions and for transmitting different influences under unfavorable traffic conditions, car-carried apparatus comprising receiving circuits including inductive receiving means adapted to have voltages induced therein by said influences, a control relay having normal and reverse energized positions and energized in accordance with the voltages in said receiving circuits, a normally energized electromagnetic device adapted to initiate an automatic brake application when de-energized and maintained energized by a circuit including contacts of said control relay closed when influences corresponding to favorable traffic conditions are received, a stick relay acting when energized to maintain said electro-magnetic device energized to permit the vehicle to proceed in said unequipped sections without an automatic brake application, a manually operable contactor acting when operated to close an energizing circuit for said stick relay provided influences of excessive magnitude are transmitted from the trackwa trackway means at the eutrance to said unequipped sections for transmitting such influences of excessive magni' tude, a stick circuit for said stick relay including contacts of said control relay closed in the reverse position, and a circuit including a car-carried source of energy for supplying influences to said receiving circuits to maintain said control relay energized in the reverse position, said circuit being closed when said stick relay is energized.

7. In an automatic train control system of the type having sections of its trackway equipped for automatic train control and sections not so equipped, trackway means in said equipped sections for continuously transmitting influences to a vehicle under favorable trafiEic conditions only, vehiclecarried apparatus comprising receiving cir cuits for receiving said influences, a control device controlled in accordance with said influences, brake applying means controlled by said control device to initiate an automatic brake application when said influences are not transmitted, trackway and car-carried meansifor rendering said brake applying device inactive atthe entrance to said unequipped sections of trackway, car-carried means including a source of energy for supplying influences to said receiving circuits for maintaining said brake applying device inactive while the vehicle is traveling in and trackway means at the entrance to said equipped sections for rendering said brake applying device active as the vehicle enters said equipped sections;

8. In an automatic train control system of the type having sections of its trackway equipped for automatic train control and sections not so equipped, trackway means in said equipped sections for continuously transmitting influences to a vehicle under favorable traffic conditions, vehicle-carried means including circuits for receiving said, influences and means for initiating an automatic brake application when said influences are not received, means for renderingsaid brake applying means inactive for vehicle travel in said unequipped sections including trackway means located at the entrance of said unequipped sections and adapted to transmit a distinctive influence to said vehicle receiving circuits, means for maintaining said brake applying means 1nactive while the vehicle is traveling in said unequipped sections including a car-carried circuit for supplying influences to said receiving circuit from a car-carried source, and trackway meanslocated at the entrance to said equipped sections for neutralizing the effect of said influences from said carcarried source, and thereby rendering said brake applying means active.

9. In an automatic train control system of the type having sections of its trackway equipped for automatic train control and sectionsnot so equipped, trackway means in said equipped sections for continuously transmitting influences to a vehicle under favorable traffic conditions ahead, vehicle receiving circuits for receiving said influences, control means controlled by said circuits for initiating an automatic brake application when no such influences are received, a car-carried source of energy, means including trackway apparatus located at the entrance to said unequipped sections and transmitting a distinctive influence for causing influences from said car-carried source to be supplied to said receiving circuit to prevent an automatic brake application when the vehicle is traveling in said unequipped sections, and means comprising trackway apparatus located at the entrance to said equipped sections and transmitting an influence for neutralizing the influence supplied from said car-carried source and thereby placing the car-carried apparatus in its active condition for vehicle travel in said equipped sections.

\ 10. In an automatic train control sys tem of the continuous inductive type, the combination with car-carried apparatus comprising a main relay, receiving means for causing said main relay to assumean energized condition in response to current of normal magnitude and flowing in a particular manner in the track rails, a normally energized brake control device having an energized circuit closed when said main relay is energized, a push button, a non-control territory relay having a pick-up circuit which is closed it said main relay is energized and said push button is depressed providing current of excess magnitude is flowing in a particular manner in the track rails, a stick circuit including a contact closed when said main relay is energized and a contact closed when said non-control territory relay is energized, means including a car-carried source of energy for energizing said main relay when said non-control relay is energized, means including said receiving means for causing said main-relay to assume its tie-energized condition in spite of its energization by said car-carried source of current when current of excess magnitude is flowing in a different particular manner in the track rails, and trackway means for supplying current of normal magnitude in the track rails in train control territory under proceed conditions, supplying current of excess magnitude in one particular manner in the track rails at the entrance to non-control territory and supplying current of excess magnitude in a different manner in the track rails at the entrance to train control territory.

11. In a train control system of the continuous inductive type comprising, a main relay on a car controlled in accordance .with the flow of current in the track rails and assuming its normal proceed condition when there is current flowing in the track rails in a certain manner, trackway equipment at;

the entrance to non-control territory for causing a current to flow in the track rails in a different manner to cause said main relay to assume a reversed condition, a noncontrol territory relay of the stick type which may be picked up-by a pick-up cire cuit and maintained stuck up if said main relay assumes its reversed condition, means wholly on the car for maintaining said main relay energized in its reversed condition efiective when said non-control relay is energized, trackway means at the entrance to train control territory for causing de-energization of said main relay in spite of its ener ization by the means wholly on the car, and rake control means tending to assume its active condition maintained inactive when said main relay assumes its normal condition.

19 A train control system of the continuous inductive type comprising, a main relay on a car controlled in accordance with the flow of current received from an amplifier having its input circuit inductively coupled with the rails of the trackway and assuming its normal proceed condition when there is current of a certain character flowing in the track rails, trackway equipment at the entrance to non-control territory for causing a current of a different character to flow in the track rails and cause said main relay to assume a reversed condition, a noncontrol territory relay of the stick type which may be picked up by a pick up 011- cuit and maintained stuck up through a stick circuit providing said main relay assumes its reverse energized condition, means wholly on the car for energizing the input circuit of said amplifier and maintaining said main relay energized in its reversed condition efiective when said non-control relay is energized, trackway means at the entrance to train control territory for causing deenergization of said main relay in spite of its energization by the means wholly on the car, and brake control means tending to assume its active condition maintained inactive when either said main relay assumes its normal condition or said non-control relay assumes its energized condition.

13. An automatic train control system of the continuous inductive type for railroads having portions of its trackway equipped for automatic train control and having portions not so equipped, brake control means, receiving means for maintaining said brake control means inactive in response to influences due to current flowing in the track rails under. clear traffic conditions, means for influencing said receiving means by a car-carried source of current to maintain said brake control means inactive while traveling in territory not equipped for automatic train control, and track means at the entrance to territory equipped for automatic train control for disconnecting the car-carried source of current to prevent it from further influencing said receiving means.

In testimony whereof I afiix my signature.

VVILMER W. SALMON. 

